The present invention relates to a multi-layer molded articles containing at least one layer of a specific anisotropic melt-forming polyester, and a process for producing same.
There has recently been an increasing demand for plastics of higher performance and a number of polymers exhibiting various novel performances have been developed and marketed. Above all, optically anisotropic liquid crystal polymers having a parallel arrangement of molecular chains have been attracting a special attention in that they have superior mechanical properties.
As polymers which form anisotropic melt there are known, for example a liquid crystal polymer prepared by copolymerizing p-hydroxybenzoic acid with polyethylene terephthalate components (JP 49072393A), a liquid crystal polymer prepared by copolymerizing p-hydroxybenzoic acid with 6-hydroxy-2-naphthoic acid (JP 54077691A), and a liquid crystal polymer prepared by copolymerizing p-hydroxybenzoic acid with 4,4'-dihydroxybiphenyl and terephthalic or isophthalic acid (JP 57024407B and JP 60025046A).
However, it is known that when those known liquid crystal polyesters are subjected to forming in a conventional manner, the resulting moldings are lower in modulus with increase of their thickness although a relatively high modulus is obtained when the moldings thickness is small [see W. J. Jackson, et al., J. Polym. Sci. Polm. Chem. Ed., 14, 2043 (1976)].